I know I’m not the only person who, while ankle-deep in muck and manure or on bended, frostbitten knees, burying flower bulbs into ice-cold autumn soil, has occasionally paused to ask myself why I garden. The answer? The simplest, and the one that leads to yet another flurry of “whys”, is that I’d be miserable if I didn’t.

It's a question that Thomas Rainer, the well-known Washington-based landscape architect, "horticultural futurist', lecturer, philosophiser and one of the key speakers at next month's much-anticipated GLDA (Garden and Landscape Designers Association) conference, returns to frequently in his award-winning gardening blog, Grounded Design.

In Rainer's case, his twitter handle, in which he describes himself as "landscape architect by profession, gardener by obsession", gives some clue as to his answer. So does his childhood, growing up in a suburban house on the edge of a large forest in Alabama in the south-east of the United States. "As a child, I would build forts in those woods, catch crawdads from the streams, and spend my weekends wandering with a pack of neighbourhood boys. It was a special place to me." That special place no longer exists, except in memory. By the time Rainer had reached high school, his beloved landscape with its hills, valleys and chattering streams had been bulldozed away by developers, to be replaced by parking lots and strip malls.

These days, Rainer lives with his wife and young son in a suburb of Washington, having first moved there as a young graduate to take up a job in the world-renowned landscape architecture firm Oehme van Sweden. But those early childhood memories of that lost forest continue to have a formative effect upon his evolution as a gardener. "As someone who now lives in the city, I look to my garden – in fact, I need my garden – as a way to recover a lost relationship I had with wildness. I'm fascinated with the art of planting design. When it is done really well –which is not very often – it can make us remember, at least intuitively, a relationship to wildness."

Serious words, but then Rainer tends to think we don’t take gardens seriously enough. “They deserve more thought, discussion and debate.”

Many agree with him; since he started his blog in 2010, his intelligent, thoughtful, ever-inquiring musings on the who, what, how, where, why, which and when of gardening have earned him a growing online-following. Not only has it led to a lecturing post at George Washington University, and an upcoming book but it's connected him "with people all over the world, people just wanting to have a conversation about design."

So while agreeing that the internet and in particular social media can have a dark, sometimes superficial side (he cites shameless self-promotion as one example), Rainer argues that for gardeners, it has also been a powerful force for good. “For the first time in history, what has been essentially a private endeavour – gardening or designing – can be shared with like-minded people all over the world. That to me is the alchemy of the internet: transforming a craving for connection, or a burning curiosity, into a real-life relationship,”

What excites him most as a gardener is the work of other innovative, cutting-edge gardeners and designers such as Fergus Garrett (of Great Dixter in the UK), Heiner Luz (the German-born landscape architect), James Hitchmough and Nigel Dunnett (of the Sheffield School in the UK) and the Blake siblings in Co Wicklow. Fellow garden and nature bloggers, too, including James Golden's Federal Twist, and Phyllis Odessey and David George Haskell's Ramble. "To me, the only great sin in gardening or garden design is cliché. It is something we always have to fight against."

His invitation to speak at this year's GLDA conference came about at the suggestion of the Dutch-born, Waterford-based garden designer and GLDA member Peter Stam. Fittingly, it followed an online conversation between Rainer and other gardeners, designers and the generally curious about the far-reaching influence of the Dutch-born designer Piet Oudolf, best known for his work on New York's Highline. Oudolf has been described as the leading prophet of the garden style popularly known as the New Perennial Movement, which uses a palette of predominantly herbaceous plants. Except as Rainer points out, it's not that new at all but is part of a much larger, older tradition whose lineage can be traced right back through the history of great garden design to the famous 19th-century Irish gardener, William Robinson.

"So you see, Ireland is really the epicentre of the New Perennial Movement. It's just 150 years removed."

Joining him as speakers at next month's GLDA conference are a clutch of other innovative, inventive and interesting garden makers including Patrick and Sylvie Quibel of Le Jardin Plume in Normandy, Keith Wiley of Wildside in Devon and Ireland's very own Verney Naylor.

For those of us who sometimes ask ourselves why we garden, it promises to be a fascinating day.

The 19th GLDA International Garden Design Seminar – 'The New Perennial Movement: Transient Trend or Adaptable Style?' takes place on Saturday, February 7th at the Crowne Plaza Hotel, Santry, Dublin 9. Tickets €60-€85, see glda.ie.

THIS WEEK IN THE GARDEN

Take a few minutes to carefully examine any overwintering stores of home-grown fruit, vegetables or flower tubers – for example, apples, squash, potatoes, dahlia tubers – and discard any that are showing signs of decay. Otherwise, if left unchecked, rot can quickly spread and destroy the entire crop.

Speaking of potatoes, now is a great time to pre-order this year's supply of seed potatoes, while stock of hard-to-get or popular varieties is still high. Of the numerous varieties available to gardeners, my favourites include 'Nicola', 'Charlotte' (both classed as second earlies), 'Orla' (second early/early maincrop) 'Cara' and 'Setanta' (both maincrop).

For varieties with exceptionally good blight resistance, choose 'Sarpo Mira' (late maincrop, available from Mr Middleton), 'Robinta' and 'Bionica' (both early maincrop, available as organic seed from Fruithill Farm) or 'Tibet' (late maincrop, available only to members of Irish Seed Savers).

One of the great joys of the winter garden is the sight and smell of the fragrant, crumpled flowers of witch hazel (Hamamelis), which are produced on the bare branches of this deciduous woody shrub from as early as December. Depending on the variety, the flowers can be lemon, bright yellow, orange, bronze, copper or deep red. Which is best? To judge for yourself and to see a fine selection of these flowering shrubs in all their winter glory, visit Mount Venus Nursery, situated in the foothills of the Dublin mountains, on one of their upcoming Hamamelis Days, Saturday January 31st and Sunday February 1st, see mountvenusnursery.com.